<?php
/**
 * AKSRT Stripe Gateway — Stripe 支付网关
 *
 * 使用 stripe/stripe-php 实现 Checkout Session 支付、Webhook 回调、退款。
 *
 * @package AKSRT
 */

defined('ABSPATH') || exit;

class AKSRT_Stripe_Gateway implements AKSRT_Payment_Gateway_Interface {

    public function get_id(): string {
        return 'stripe';
    }

    public function get_name(): string {
        return __('Stripe', 'aksrt');
    }

    public function is_configured(): bool {
        $config = $this->get_config();
        return !empty($config['secret_key']) && !empty($config['publishable_key']);
    }

    public function create_payment(array $order): array {
        if (!$this->is_configured()) {
            return ['success' => false, 'message' => __('Stripe 未配置', 'aksrt')];
        }

        $config = $this->get_config();
        $order_number = $order['order_number'] ?? '';
        $amount = (float) ($order['amount'] ?? 0);
        $subject = $order['subject'] ?? __('订单支付', 'aksrt');
        $currency = strtolower($config['currency'] ?? 'usd');

        try {
            $stripe = $this->create_client($config);

            // 创建 Checkout Session
            $session_params = [
                'payment_method_types' => $this->get_payment_methods($config),
                'line_items' => [[
                    'price_data' => [
                        'currency'     => $currency,
                        'product_data' => [
                            'name' => $subject,
                        ],
                        'unit_amount'  => $this->to_smallest_unit($amount, $currency),
                    ],
                    'quantity' => 1,
                ]],
                'mode' => 'payment',
                'success_url' => home_url('/wp-json/aksrt/v1/payment/stripe/return?session_id={CHECKOUT_SESSION_ID}&order=' . $order_number),
                'cancel_url'  => home_url('/wp-json/aksrt/v1/payment/stripe/cancel?order=' . $order_number),
                'metadata'    => [
                    'order_number' => $order_number,
                ],
            ];

            // 启用自动支付方式（Apple Pay, Google Pay 等）
            if (!empty($config['auto_payment_methods'])) {
                $session_params['automatic_payment_methods'] = [
                    'enabled' => true,
                ];
            }

            $session = \Stripe\Checkout\Session::create($session_params, [
                'api_key' => $config['secret_key'],
            ]);

            return [
                'success'      => true,
                'payment_url'  => $session->url,
                'payment_data' => [
                    'order_number' => $order_number,
                    'session_id'   => $session->id,
                ],
                'message'      => __('Stripe 支付页面已创建', 'aksrt'),
            ];
        } catch (\Stripe\Exception\ApiErrorException $e) {
            return ['success' => false, 'message' => $e->getMessage()];
        } catch (\Exception $e) {
            return ['success' => false, 'message' => $e->getMessage()];
        }
    }

    public function verify_callback(WP_REST_Request $request): array {
        $config = $this->get_config();

        try {
            $stripe = $this->create_client($config);

            $payload = $request->get_body();
            $sigHeader = $_SERVER['HTTP_STRIPE_SIGNATURE'] ?? '';

            // 验证 Webhook 签名
            $event = \Stripe\Webhook::constructEvent(
                $payload,
                $sigHeader,
                $config['webhook_secret'] ?? ''
            );

            if ($event->type !== 'checkout.session.completed') {
                return ['success' => false, 'message' => __('非支付完成事件', 'aksrt')];
            }

            $session = $event->data->object;
            $orderNumber = $session->metadata->order_number ?? '';
            $amount = ($session->amount_total ?? 0) / 100;

            return [
                'success'        => true,
                'order_number'   => $orderNumber,
                'amount'         => $amount,
                'transaction_id' => $session->payment_intent ?? $session->id,
                'status'         => $session->payment_status === 'paid' ? 'paid' : 'pending',
            ];
        } catch (\Stripe\Exception\SignatureVerificationException $e) {
            return ['success' => false, 'message' => __('Webhook 签名验证失败', 'aksrt')];
        } catch (\Exception $e) {
            return ['success' => false, 'message' => $e->getMessage()];
        }
    }

    public function query_status(string $order_number): array {
        if (!$this->is_configured()) {
            return ['success' => false, 'message' => __('Stripe 未配置', 'aksrt')];
        }

        $config = $this->get_config();

        try {
            $stripe = $this->create_client($config);

            // 注意：Stripe API 的 Session::all() 不支持按 metadata 过滤。
            // 此处通过创建时间倒序获取最近的 session，再匹配 metadata。
            // 生产环境建议在 create_payment 时保存 session_id 并用 Session::retrieve() 查询。
            $sessions = \Stripe\Checkout\Session::all([
                'limit' => 100,
            ], ['api_key' => $config['secret_key']]);

            // 手动按 metadata 匹配
            $found = null;
            foreach ($sessions->data as $session) {
                if (($session->metadata->order_number ?? '') === $order_number) {
                    $found = $session;
                    break;
                }
            }

            if ($found) {
                $status = 'pending';
                if ($found->payment_status === 'paid') {
                    $status = 'paid';
                } elseif ($found->status === 'expired') {
                    $status = 'cancelled';
                }

                return [
                    'success'        => true,
                    'status'         => $status,
                    'transaction_id' => $found->payment_intent ?? '',
                ];
            }

            return ['success' => true, 'status' => 'pending', 'message' => __('未找到支付记录', 'aksrt')];
        } catch (\Exception $e) {
            return ['success' => false, 'message' => $e->getMessage()];
        }
    }

    public function refund(string $order_number, float $amount): array {
        if (!$this->is_configured()) {
            return ['success' => false, 'message' => __('Stripe 未配置', 'aksrt')];
        }

        $config = $this->get_config();

        try {
            $stripe = $this->create_client($config);

            // 先查询 payment_intent（手动按 metadata 匹配）
            $sessions = \Stripe\Checkout\Session::all([
                'limit' => 100,
            ], ['api_key' => $config['secret_key']]);

            $found = null;
            foreach ($sessions->data as $session) {
                if (($session->metadata->order_number ?? '') === $order_number) {
                    $found = $session;
                    break;
                }
            }

            if (!$found) {
                return ['success' => false, 'message' => __('未找到支付记录', 'aksrt')];
            }

            $paymentIntentId = $found->payment_intent;

            if (empty($paymentIntentId)) {
                return ['success' => false, 'message' => __('未找到支付意图', 'aksrt')];
            }

            $currency = strtolower($config['currency'] ?? 'usd');

            $refund = \Stripe\Refund::create([
                'payment_intent' => $paymentIntentId,
                'amount'         => $this->to_smallest_unit($amount, $currency),
                'reason'         => 'requested_by_customer',
            ], ['api_key' => $config['secret_key']]);

            return [
                'success'   => true,
                'refund_id' => $refund->id,
                'message'   => __('退款成功', 'aksrt'),
            ];
        } catch (\Stripe\Exception\ApiErrorException $e) {
            return ['success' => false, 'message' => $e->getMessage()];
        } catch (\Exception $e) {
            return ['success' => false, 'message' => $e->getMessage()];
        }
    }

    /**
     * 获取 Stripe Publishable Key（前端使用）。
     */
    public function get_publishable_key(): string {
        $config = $this->get_config();
        return $config['publishable_key'] ?? '';
    }

    private function get_config(): array {
        // 优先从统一设置读取（schema 保存的 key）
        if (class_exists('AKSRT_Settings')) {
            $all = AKSRT_Settings::get_all();
            if (!empty($all['stripe_secret_key'])) {
                return [
                    'secret_key'      => $all['stripe_secret_key'] ?? '',
                    'publishable_key' => $all['stripe_publishable_key'] ?? '',
                    'webhook_secret'  => $all['stripe_webhook_secret'] ?? '',
                    'currency'        => $all['stripe_currency'] ?? 'usd',
                    'mode'            => !empty($all['stripe_test_mode']) ? 'test' : 'live',
                ];
            }
        }
        // 回退到独立 option
        $settings = get_option('aksrt_payment_stripe', []);
        return is_array($settings) ? $settings : [];
    }

    private function create_client(array $config): void {
        \Stripe\Stripe::setApiKey($config['secret_key']);

        // 设置 API 版本
        \Stripe\Stripe::setApiVersion('2023-10-16');

        // 启用遥测（可选）
        if (!empty($config['enable_telemetry'])) {
            \Stripe\Stripe::setEnableTelemetry(true);
        }
    }

    /**
     * 获取支持的支付方式。
     */
    private function get_payment_methods(array $config): array {
        $methods = $config['payment_methods'] ?? ['card'];

        // 验证支付方式
        $valid = ['card', 'alipay', 'wechat_pay', 'sepa_debit', 'ideal', 'bancontact', 'giropay', 'sofort'];
        return array_values(array_intersect($methods, $valid)) ?: ['card'];
    }

    /**
     * 将金额转换为最小单位（分/cent）。
     */
    private function to_smallest_unit(float $amount, string $currency): int {
        // 零小数货币（日元、韩元等）
        $zeroDecimal = ['bif', 'clp', 'djf', 'gnf', 'jpy', 'kmf', 'krw', 'mga', 'pyg', 'rwf', 'ugx', 'vnd', 'vuv', 'xaf', 'xof', 'xpf'];

        if (in_array(strtolower($currency), $zeroDecimal, true)) {
            return (int) $amount;
        }

        return (int) round($amount * 100);
    }
}